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Title: Electromagnetic wave attenuation measurements in a ring-shaped inductively coupled air plasma

An aerocraft with the surface, inlet and radome covered large-area inductive coupled plasma (ICP) can attenuate its radar echo effectively. The shape, thickness, and electron density (N{sub e}) distribution of ICP are critical to electromagnetic wave attenuation. In the paper, an air all-quartz ICP generator in size of 20 × 20 × 7 cm{sup 3} without magnetic confinement is designed. The discharge results show that the ICP is amorphous in E-mode and ring-shaped in H-mode. The structure of ICP stratifies into core region and edge halo in H-mode, and its width and thickness changes from power and pressure. Such phenomena are explained by the distribution of RF magnetic field, the diffusion of negative ions plasma and the variation of skin depth. In addition, the theoretical analysis shows that the N{sub e} achieves nearly uniform within the electronegative core and sharply steepens in the edge. The N{sub e} of core region is diagnosed by microwave interferometer under varied conditions (pressure in range of 10–50 Pa, power in 300–700 W). Furthermore, the electromagnetic wave attenuation measurements were carried out with the air ICP in the frequencies of 4–5 GHz. The results show that the interspaced ICP is still effective to wave attenuation, and the wave attenuation increases with themore » power and pressure. The measured attenuation is approximately in accordance with the calculation data of finite-different time-domain simulations.« less
Authors:
; ; ;  [1] ;  [2]
  1. Science and Technology on Plasma Dynamics Laboratory, Air Force Engineering University, Xi'an 710038 (China)
  2. Institute of Aerospace Engineering, Air Force Engineering University, Xi'an 710038 (China)
Publication Date:
OSTI Identifier:
22410241
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 20; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; AIR; ANIONS; APPROXIMATIONS; ATTENUATION; COMPUTERIZED SIMULATION; DIFFUSION; ELECTRON DENSITY; GHZ RANGE; H-MODE PLASMA CONFINEMENT; MAGNETIC FIELDS; MICROWAVE RADIATION; PLASMA; PLASMA DIAGNOSTICS; PLASMA SIMULATION; QUARTZ